Solder & Low-Melting Alloy Wood's Metal
also Cerrobend
Wood's Metal (Cerrobend) is the classic bismuth-lead-tin-cadmium fusible alloy melting near 70 °C, used long before cadmium-free formulations existed.
Reference datasheet — Wood's Metal is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the F condition
Wood's Metal tempers and conditions
Wood's Metal is supplied in 2 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
FDefault As fabricated | Default condition: melted in hot water/oil bath and poured into the cavity or fusible plug body. | 25 | 42 | 25 | 11 HB | 3 % IACS |
Cast, room-temperature aged ≥24 h | Use when dimensional stability matters (dies, holding fixtures): the slight post-cast growth of the Bi phase has finished after about a day. | 30 | 48 | 18 | 13 HB | 3 % IACS |
Supply forms, finishes and certifications
Ways Wood's Metal is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Ingot | Ingot / bar stock for remelting | Supply form |
SHOT | Shot / granules / powder | Supply form |
WIRE | Extruded wire / rod | Supply form |
What is Wood's Metal?
Wood's Metal (Cerrobend) is the classic bismuth-lead-tin-cadmium fusible alloy melting near 70 °C, used long before cadmium-free formulations existed. It casts with near-zero shrinkage and melts out in hot water, which is why it was standard for fusible safety devices, tube-bending fills and pattern work; it is supplied as ingot, wire and shot in F and aged conditions. Properties are 42 MPa tensile, 25% elongation and 11 HB with service capped near 40 °C. Cadmium and lead content have largely phased it out of new designs — Field's Metal is the non-toxic replacement at a similar melting range. Wood's Metal has a density of 9.7 g/cm³ (0.35 lb/in³), heavier than 70% of solder & low-melting alloy grades. It melts at 70°C (158 °F). Wood's Metal has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 61% of solder & low-melting alloy grades. Elongation at break is 25% and the elastic modulus is 9.7 GPa (1.41 Msi).
What is Wood's Metal used for?
- fire sprinkler fusible links
- tube bending fill alloy
- fusible safety plugs
- pattern/mold making
Advantages
- Low embodied carbon — 4 kg CO₂/kg, better than 80% of solder & low-melting alloy grades
Limitations
- Low stiffness — 9.7 GPa (1.41 Msi), worse than 100% of solder & low-melting alloy grades
- Poor heat conductor — 13 W/m·K (7.51 BTU/hr·ft·°F), worse than 99% of solder & low-melting alloy grades
- Low electrical conductivity — 3 % IACS, worse than 98% of solder & low-melting alloy grades
- Limited service temperature — 40°C (104 °F), worse than 97% of solder & low-melting alloy grades
- Limited formability — 40/100, worse than 83% of solder & low-melting alloy grades
Wood's Metal properties
Typical room-temperature values for Wood's Metal-F; bars are the position among solder & low-melting alloy grades.
Physical3
Wood's Metal has a density of 9.7 g/cm³ (0.35 lb/in³), heavier than 70% of solder & low-melting alloy grades. It melts at 70°C (158 °F).
Mechanical13
Wood's Metal has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 61% of solder & low-melting alloy grades. Elongation at break is 25% and the elastic modulus is 9.7 GPa (1.41 Msi).
Thermal6
Wood's Metal is rated for continuous service to 40°C (104 °F). It conducts heat at 13 W/m·K (7.51 BTU/hr·ft·°F), worse than 99% of solder & low-melting alloy grades. Thermal expansion is 23 µm/m·K (12.8 µin/in·°F).
Electrical3
Wood's Metal conducts electricity at 3 % IACS, worse than 98% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 90% of solder & low-melting alloy grades.
Sustainability3
Producing a kilogram of Wood's Metal takes about 55 MJ of energy and emits 4 kg of CO₂ — less than 79% of solder & low-melting alloy grades. Typical recycled content is 40%.
Manufacturability8
Wood's Metal's machinability is fair (35/100, better than 58% of solder & low-melting alloy grades); weldability poor (15/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the solder & low-melting alloy family
Yield strength against density for every solder & low-melting alloy grade FabDigit runs. Wood's Metal is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Wood's Metal
Is Wood's Metal easy to machine?
Cuts easily but smears and can melt from cutting heat — use sharp HSS tools, high rake, flood coolant, and capture all chips as hazardous Pb/Cd waste.
Can Wood's Metal be welded?
Not weldable in the usual sense; joints are made by simply remelting the alloy at 70–100 °C in a water or oil bath.
Can Wood's Metal be formed, bent or molded?
Gravity or hand pour at 80–100 °C into silicone, plaster or metal moulds; near-zero shrinkage reproduces fine detail, and cast tube-bending cores are removed by hot-water melt-out.
Wood's Metal chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Bieutectic base, gives near-zero solidification shrinkage | 49 – 51 | 50 |
| Pb | 25.5 – 27.5 | 26.7 |
| Sn | 12.5 – 14 | 13.3 |
| Cdtoxic; reason for RoHS/REACH restriction | 9.5 – 10.5 | 10 |
| impurities (Sb, Cu, Zn, Fe, As)total, typical commercial limit | ≤ 0.15 |
What surface finishes work on Wood's Metal?
Too soft to polish or plate practically; surfaces tarnish grey, so leave as-cast and never use in food, skin or potable-water contact.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Wood's Metal in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Cerrobend
How much does Wood's Metal cost?
Wood's Metal is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Wood's Metal — frequently asked
What is Wood's Metal used for?
Wood's Metal is typically used for fire sprinkler fusible links, tube bending fill alloy, fusible safety plugs and pattern/mold making. In short: 70 °C melting fusible alloy; near-zero casting shrinkage; cd/Pb-bearing legacy grade.
What is the yield strength of Wood's Metal?
Wood's Metal has a typical yield strength of 25 MPa (3.63 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 61% of solder & low-melting alloy grades. Strength varies by condition: see the 2 listed tempers.
Is Wood's Metal easy to machine?
Not especially — machinability is rated fair (35/100, better than 58% of solder & low-melting alloy grades). Cuts easily but smears and can melt from cutting heat — use sharp HSS tools, high rake, flood coolant, and capture all chips as hazardous Pb/Cd waste.
Can Wood's Metal be welded?
Not readily — weldability is rated poor (15/100). Not weldable in the usual sense; joints are made by simply remelting the alloy at 70–100 °C in a water or oil bath.
What surface finishes work on Wood's Metal?
Too soft to polish or plate practically; surfaces tarnish grey, so leave as-cast and never use in food, skin or potable-water contact.
Can Wood's Metal be formed, bent or molded?
Gravity or hand pour at 80–100 °C into silicone, plaster or metal moulds; near-zero shrinkage reproduces fine detail, and cast tube-bending cores are removed by hot-water melt-out.
What is the maximum service temperature of Wood's Metal?
Wood's Metal is rated for continuous use to about 40°C (104 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Wood's Metal-F and Wood's Metal F-AGED?
F is the default condition — default condition: melted in hot water/oil bath and poured into the cavity or fusible plug body. F-AGED: use when dimensional stability matters (dies, holding fixtures): the slight post-cast growth of the Bi phase has finished after about a day. Yield strength is 25 MPa in F versus 30 MPa in F-AGED.
How much does Wood's Metal cost?
Wood's Metal is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Low-Melting/Fusible Alloys) — ASM International (1990)
- Cerrobend / fusible alloy technical data (70 °C eutectic) — fusible-alloy producers (2020)
- CRC Handbook of Chemistry and Physics — low-melting alloy data — CRC Press (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.